Download Organisational Complexity of the Human Circulation System

Organisational
Complexity of the Human
Circulation System
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The way a closed circulation system is organised
Arteries, arterioles, veins, venules and capillaries
Pulmonary & systemic circulation and portal systems
Structure of the heart & path of blood through it
Role of muscle and valves in heart and blood vessels
Coronary arteries & veins supplying the heart muscle
Lymphatic system
ABO blood groups
Pulse
Composition of blood
Rhesus Factor
Blood pressure
Substance can move through very small animals by diffusion
Two types of Circulation System
1. Open Circulation Systems
Heart pumps blood into vessels that are open ended ……e.g. in Insects
2. Closed Circulation Systems
Blood remains in a continuous system of blood vessels…..e.g. in Humans
Advantages of a Closed Circulation System
1.
Blood can be pumped faster
Therefore nutrients can be delivered faster to cells allowing the organism to be
more active
2.
Blood flow rate to different organs
can be changed
For example blood flow can be increased to the leg mucles
when running
Main parts of Human Circulation System
1.
Heart
2
Blood Vessels
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Blood
Arteries
Arterioles
Veins
Venules
Capillaries
Role of muscle and elastic fibres
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Muscle expands to allow increased blood flow through the vessel
Elastic fibres contracts the blood vessel back to shape.
Valves prevent backflow
Arteriole
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Arterioles connect arteries and capillaries
Venules
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venules connect capillaries to the veins
Capillaries
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Tiny blood vessels linking arterioles and venules
The thin wall allows easy exchange of materials with cells
The Heart
Location
Between the lungs, slightly to the left side of the thorax, above the diaphragm
Function
To pump blood around the body
Structure
A hollow structure made of cardiac muscle, surrounded by a double membrane
Role of Heart Muscle
1.
The heart wall is made of Cardiac Muscle
2.
Contraction of the cardiac muscle drives blood around the body
3.
Cardiac Muscle does not fatigue
Advantages of a Double Circulation System
1.
Separation of oxygen rich and oxygen poor blood
2.
Blood pressure can be kept
high
Portal systems
A blood pathway that begins and ends in capillaries
Hepatic Portal System
Connects the stomach and intestines with the liver
Structure of the heart
Role of Valves
Tricuspid valve
Prevents backflow into right atrium
Semi Lunar valves
Prevent backflow into heart
Bicuspid Valve
Prevents backflow into left atrium
Blood supply to the heart wall
Coronary arteries
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Cardiac muscle is supplied with blood by the coronary arteries. These branch from the
aorta just above the semi lunar valves
Coronary veins
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Drain blood from heart wall into the right atrium
Heartbeat and its control
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The heart beat consists of
alternate contraction and
relaxation of the cardiac
muscle
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The heart beat is
controlled by the
pacemaker in the right
atrium. This sends an
electrical signal to the
cardiac muscle
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The heart beat sound is
caused by the closing of
the heart valves
Pulse
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The alternate expansion and contraction of arteries is called a pulse
Average pulse rate is 72 beats per minute
Blood Pressure
Pressure is due to the contraction of the ventricles which forces blood into the arteries
Effect of smoking on the circulation system
1. Nicotine increases the heart rate and blood pressure. These puts a bigger workload on the
heart
2. CO2 reduces the amount of O2 carried by the blood. This reduces energy levels
3. Other chemicals in tobacco. Increase the chance of clots
Effect of Diet on the circulation system
1. High intake of fat causes a build-up of cholesterol. Cholesterol may block arterioles and lead
to stroke or heart attack
2. High salt intake . Raises blood pressure which can cause heart attack
Effect of Exercise on the circulation system
1. Exersise strengthens the heart. Exersise strengthens the heart. This improves circulation
2. Exercise increases our ability to transport oxygen. This gives increased energy levels
Lymphatic System
 A secondary transport system consisting of one way system of vessels that collects and
returns excess tissue fluid to blood
system
Structure
1.
Lymph vessels
2.
Lymph Nodes
3.
Lymph
Lymphatic System Functions
1.
Collect tissue fluid and return it to the
2.
Fight Infection by
blood system
(a) Filtering out microorganisms in the lymph nodes
(b) Destroying microorganisms by antibody production
(c) Mature and store lymphocytes
3.
Transport digested fat away from intestine